As a method of detecting an analyte that should be detected in a sample through an antigen-antibody reaction, a measurement method using an immunochromatographic test strip has been conventionally performed. In immunochromatography, an antibody or an antigen to its antigen or antibody defined as an analyte is immobilized onto an insoluble membrane support that is a chromatograph medium to create a detecting section that is a stationary phase; a conjugate (a detection reagent), i.e., a label sensitized by an antibody or antigen capable of binding to the analyte is used as a mobile phase; the analyte is specifically reacted with the conjugate that is a mobile phase; and, in the detecting section that is a stationary phase, the analyte bound to the conjugate is specifically reacted with the antibody or antigen immobilized to the detecting section. Since metal colloid particles such as colloidal gold and colored latex particles are typically used as the label, the presence, or an amount in some cases, of the analyte in the sample is detected from color in the detecting section.
As described in Patent Literature 1, a configuration of an immunochromatographic test strip generally includes a sample pad for supplying a sample, a conjugate pad for disposing the conjugate that is the mobile phase, an insoluble membrane support developing a complex between the sample and the conjugate and having a detecting section for detection, and an absorbent pad for absorbing the sample developed through the insoluble membrane support.
However, since the conjugate is not easily released from the conjugate pad, the conventional immunochromatographic test strip configured as above has a problem that it takes time for completing the reaction or that the background tends to be high.
Although the conjugate pad is uniformly impregnated with the conjugate and dried, a step of impregnation with the conjugate makes automation of manufacturing difficult and tends to result in non-uniform impregnation with the conjugate, which may cause a problem of variation in performance.